At last... Martin Scorsese with his Oscar for best direction. Photograph: Paul Buck/EPA

Martin Scorsese had sat through too many Oscar ceremonies to believe what he was being told. "Could you double-check the envelope, please?" he asked, after being presented with the award for best director at his sixth attempt.

Better was to come for The Departed as his film won the next and biggest award, best picture, the culmination of Sunday night's ceremony at the Kodak Theater.

A chilly evening failed to dampen the mood of the film-world elite and the hundreds who lined the long red carpet on Hollywood Boulevard. Oscar contenders old and new, from Mickey Rooney to Abigail Breslin, 10-year-old star of best picture nominee Little Miss Sunshine, acknowledged the crowd's cheers and the shouts of reporters as they walked to the theatre.

While the competition for best picture had been one of the most open for years, one of the few certainties going into the night was confirmed, when Helen Mirren won the Oscar for best actress for her performance in The Queen. Bookmakers stopped taking bets on Mirren days ago.

Speaking after receiving her award, Mirren thanked the royal family for allowing the film to be made. "There's many countries in the world that one would not be allowed to make this film," she said. "And I think it's generous of the royal family and Her Majesty the Queen to sit back and not interfere, and I think it's very gracious and very noble of her." The appreciation was mutual. Buckingham Palace said the monarch was pleased at Mirren's success and indicated that the actor could expect an invitation to meet the Queen, possibly for lunch.

Mirren's victory stood out in a night of disappointment for the many British nominees. Paul Greengrass (United 93) and Stephen Frears (the Queen) were both beaten by Scorsese, while Mirren beat Kate Winslet and Judi Dench.

Peter O'Toole weathered the attention with good grace as he left his eighth Oscars with just a nomination for best actor in Venus. And while American commentators had engaged in much soul-searching about the superiority of British acting, all the other awards were claimed by Americans, led by Forest Whitaker.

But the night belonged to Scorsese and the team behind The Departed, including its British producer Graham King. The signs that Scorsese might finally win the Oscar much of his career has merited came when three of his oldest Hollywood friends took to the stage to present the best director award: Francis Ford Coppola, Steven Spielberg and George Lucas.

"I just want to say too that so many people over the years have been wishing this for me," Scorsese said, Oscar in hand. "Strangers. You know, I went walking in the street, people say something to me. I go in a doctor's office, I go in a whatever. Elevators, people saying, 'You should win one, you should win one.' I go for an x-ray, 'You should win one.'"

But he insisted that the lack of success may have helped his film-making. "If it wasn't meant in the cards," he said backstage, "that's life. The incredible thing is I got to make these movies I really wanted to make. Mean Streets, Taxi Driver, Raging Bull ... Last Temptation of Christ and Goodfellas, who can complain."

The Departed, the bloody tale of a Boston gang, is a remake of a 2002 Hong Kong thriller Infernal Affairs, and thus becomes the first remake to win best picture Oscar since Ben Hur in 1959.

Scorsese indicated he would be interested in making a sequel, although he admitted a prequel might be more appropriate given its bloody ending.

One of the night's biggest and unlikeliest winners was the former vice-president, Al Gore. His documentary about global warming, An Inconvenient Truth, won the Oscar despite strong opposition. A song from the film, I Need to Wake Up by Melissa Etheridge, also won an award.

While backstage he reiterated that he would not run for president, and pushed his other campaign, to warn of the likely effects of global warming, and to turn the Oscars green. On a night of few surprises the 2007 Academy Awards, with its emphasis on organic food and hybrid vehicles, may be remembered as the first "carbon neutral" Oscars.

Winners

Best picture The Departed Best actor Forest Whitaker, The Last King of Scotland Best actress Helen Mirren, The Queen Best supporting actor Alan Arkin, Little Miss Sunshine Best supporting actress Jennifer Hudson, Dreamgirls Best directing Martin Scorsese, The Departed Best foreign language film Das Leben der Anderen (The Lives of Others) - Germany Best adapted screenplay William Monahan (The Departed) Best original screenplay Michael Arndt (Little Miss Sunshine) Best animated feature film Happy Feet Best art direction Pan's Labyrinth Best cinematography Pan's Labyrinth Best sound mixing Dreamgirls Best sound editing Letters from Iwo Jima Best original score Babel (Gustavo Santaolalla) Best song I Need to Wake Up, from An Inconvenient Truth (Melissa Etheridge) Best costume Marie Antoinette Best documentary feature An Inconvenient Truth Best documentary (short subject) Blood of Yingzhou District Best film editing The Departed Best makeup Pan's Labyrinth Best animated short film The Danish Poet Best live action short film West Bank Story Best visual effects Pirates of the Caribbean: Dead Man's Chest